Projectiles to be slidably fitted on the end of a gun barrel



H. Hbsu 3,098,447

PROJECTILES TO BE SLIDABLY FITTED ON THE END OF A GUN BARREL July 23, 1963 2 Sheets-Sheet 1 Filed April 27. 1961 INVEN TOR 44/v\s 339K013 /%5AT BY 'ZTM July 23, 1963 H. HbsLl 3,09

PROJECTILES TO BE SLIDABLY FITTED ON THE END OF A GUN BARREL Filed April 27, 1961 2 SheetsSheet 2 INVE N TOR The present invention releates to projectiles intended to be slidably fitted on the end of gun barrels so that cornbustion of a launching charge causes a high increase of pressure in said barrel and launches the projectile in the forward direction. This invention is more especially but not exclusively concerned with projectiles of this kind in the form of grenades to be launched by means of a quick firing or semi-automatic gun.

The object of this invention is to provide a projectile of this kind which is better adapted to meet the requirements of practice than those known up to now, in particular concerning accuracy of firing.

The invention relates to projectiles of this kind including a tubular tail arranged for slidable fitting with respect to the gun barrel and provided in its side wall with at least one transverse nozzle extending through the wall of said tail in a direction inclined to the radial direction and through which a portion of the propelling gases present in said tubular tail can escape to the external atmosphere, during at least a portion of the displacement of said tail disengaging it from the gun barrel, in such manner as to spin said projectile about its longitudinal axis. The invention is characterized by the combination with such a structure of an auxiliary jet motor carried by the projectile for self-propulsion thereof, the rearward nozzle of this auxiliary motor opening into the front end of said tubular tail.

Preferred embodiments of the present invention will be hereinafter described with reference to the accompanying drawings, given merely by way of example and in which:

FIG. 1 diagrammatically shows, in axial section with parts cut away, the rear portion of a self-propelled grenade made according to a first embodiment of the invention, this grenade being slidably fitted on the top end of a gun barrel.

FIG. 2 is a cross-sectional view on an enlarged scale on the line II--II of FIG. 1.

FIGS. 3 and 4 are views similar to FIGS. 1 and 2, respectively, of a grenade made according to a second embodiment of the invention.

FIG. 5 is a view similar to FIG. 1, showing a grenade made according to a third embodiment of the invention.

FIG. 6 is a part side view of a grenade made according to a fourth embodiment of the invention.

FIG. 7 is a cross-sectional view on the line VIIVII of FIG. 6.

The gun barrel is designated by reference numeral 1. The grenade to be launched from this gun barrel comprises, as shown by FIG. 1, a warhead 2 and a rocket motor 3 (for instance of the powder type) mounted in line with said warhead and behind it. The whole is mounted on a tubular tail 4- adapted to be slidably fitted 3,098,447 Patented July 23, 1963 on the end of gun barrel .1. The rearward nozzle of rocket 3 opens into the front end of tubular tail 4.

In the construction of FIGS. 1 and 2 and also in those shown by FIGS. 5 to 7, tubular tail 4 sumotunds the gun barrel, whereas in the construction of FIGS. 3 and 4 tail 4 is fitted inside an extension 5 of gun barrel 1.

Both of these solutions may be used according to the present invention but the first one is preferable, in particular because it permits of easily fixing tail blades 6 on the rear end of tail 4 and also because it permits of making use, for launching the grenade, of a gun provided with a muzzle brake 7 the openings of which are closed by tubular tail 4 at the time of launching. The following description will refer more especially to the first of these two solutions.

7 According to this invention, as visible in FIG. 2, the tubular tail 4 is provided with transverse inclined or, as they will be hereinafter called, tangential nozzles 8 through which a portion or the propelling gases present inside tubular tail 4 can escape to the external atmosphere during at least a portion of the displacement of the projectile disengaging tail 4 from gun barrel 1, the gas jets that escape through said tangential nozzles 8 producing a torque which causes the projectile to spin about its longitudinal axis. Initially, this action will be produced only by the gases resulting from the combustion of the launching cartridge. But subsequently, as soon as the auxiliary motor 3 is brought into action, the gases resulting from its operation will in turn escape through passages 8 and will keep the grenade spinning about its axis.

It should be noted that the supplementary spinning efiect due to the gases supplied by the rocket motor is particularly advantageous in view of the low speed of the grenade when it leaves the launching gun. It is known that this speed is chosen relatively low to reduce the recoil imparted to the launching gun, the projectile being subsequently accelerated by the rocket motor. is therefore important to have the rotating action continued after tail 4 has disengaged from barrel 1, so as to be able to obtain the desired spin.

Preferably, passages or nozzles 8 are so located in the tail that the propelling gases can begin to escape at least at the end of the first half of the displacement of tubular tail 4 disengaging it from barrel 1. Preferably, the gases are allowed to escape through nozzles '8 already during the first fourth of this displacement.

Said tangential nozzles 8 may, as shown by FIGS. 3 and 4, remain closed during the beginning of the disengagement displacement. They may also, as in the construction shown by FIG. 5, be already open at the beginning of said disengagement and then remain open to the end. In the first case, the pressure increases more quickly in the gun barrel than in the second case. But in the second case, on the contrary, there is obtained a substantial reduction of the deflection of the trajectory caused by launching, which is, so to speak, steadied, Whereas the recoil of the launching gun is reduced.

Finally when, as illustrated by FIG. 1, tubular tail 4 covers a muzzle brake 7 carried by the front end of barrel 1, tangential nozzles 8 may initially communicate with the outlets of the muzzle brake, as shown by FIG. 2. A clearance such as indicated in dotted lines at 9 in FIGS. 1 and 2 may be provided to permit a continuous access of the gases to tangential nozzles 8. Such a continuous access of the gases to nozzles 8 may also be obtained with the arrangement illustrated by FIG. 5.

In order to obtain a torque to rotate the grenade about its longitudinal axis, different means may be used.

In the construction of FIGS. 12 and 34 the nozzles 3 extending through the wall of tubular tail 4 are tangential nozzles arranged like the passages of a centrifugal radial turbine. In the construction of FIGS. 67 trans verse nozzles 8, which may have any suitable direction, cooperate with fin elements 10 curved in such manner that they act as deflectors for the gas jets issuing from said nozzles '8, thus producing the desired torque.

It should be noted that in some cases it may he of interest to make said fin elements 10 (which may be the stabilizing fins of the tail unit of the grenade but which may also be distinct therefrom) in such manner that, once the grenade has been launched on its trajectory, said wall elements 10 apply thereto a torque either in one direction or in the other, due to the reaction of air. Thus said wall elements 10 may be given a helical shape as visible on FIG. 6.

Of course if the warhead is such (in particular if it carries a hollow charge) that too fast a rotation thereof about its axis has a detrimental effect, the elements 10' or the radial blades forming the stabilizing tail unit of the grenade may be shaped to brake the initial rotation imparted to the grenade by the gases flowing out through passage 8. Thus elements 10 may be given a shape which is not a helical one or they may be given a helical shape with a pitch greater than that necessary to maintain the initial spin of the grenade about its axis. Thus the rate of spin decreases to the desired degree along the trajectory.

Anyway the spin imparted to the grenade at the beginning of its trajectory steadies its movement as above indicated and improves the accuracy of firing.

Of course the number of nozzles 8 and their crosssection areas are determined experimentally in every particular case to obtain the desired results. These nozzles must brake the flow of gases therethrough sufficiently to permit of obtaining the desired initial velocity of the pro jectile. On the other hand, they must permit a suflicient flow of gases therethrough to achieve the desired spin of the grenade about its axis.

If necessary, a launching ammunition having a reinforced charge may be used to compensate for the reduction of initial velocity of the grenade due to the outflow of a portion of the propelling gases through tangential nozzles 8. The launching ammunition may be carried by the projectile itself or it may be housed in the gun barrel.

In a general manner, while I have, in the above description, disclosed what I deem to be practical and efficient embodiments of my invention, it should be well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope of the accompanying claims.

What I claim is:

l. A projectile adapted to be launched from a gun barrel having a cylindrical surface by the pressure created from a propelling charge in the gun, the gun barrel being of the type which includes at least one passage through its wall in the vicinity of the muzzle, which projectile comprises: a body portion, a tubular tail having its front end fixed to said body portion, said tubular tail having a cylindrical surface adapted to slidably and substantially sealingly engage such a cylindrical surface of the gun from which the projectile is to be fired, a rocket motor carried by said body portion, said rocket motor comprising a reaction charge and a rearwardly directed nozzle opening into said tubular tail at the forward end thereof, and means for causing said projectile to spin about its longitudinal axis, first by utilizing the action of pressurized gases from the combustion of a propelling charge in a launching gun and then by utilizing the reaction effect of pressurized gases from the combustion of said reaction charge, said means comprising at least two transverse nozzles extending through the wall of said tubular tail rearwardly of the most rearward extension of said body portion, whereby gases issuing through said transverse nozzles have free access to the surrounding atmosphere when said transverse nozzles are clear of a gun barrel from which the projectile is to be launched, said tubular tail providing a continuously open path between the rear end of the tail and the rocket motor nozzle whereby hot gases created by the combustion of a propelling charge in a gun from which the projectile is to be launched may pass through the tubular tail and the rocket motor nozzle to ignite said reaction charge, at least one of said transverse nozzles being physically located so as to be selectively communicable with the passage through the barrel wall in the vicinity of the gun barrel muzzle when the projectile is mounted on the barrel.

2. A projectile as recited in claim 1 wherein at least one of said transverse nozzles is located in said tubular tail forward of the furthermost point to which the barrel of a launching gun may extend into said tubular tail, whereby at least one of said transverse nozzles provides a constant path of egress of pressurized gases from the tubular tail even when the tubular tail is mounted on the barrel of a gun from which the projectile is to be launched.

3. A projectile as recited in claim 1 further including stop means on said tubular tail for limiting the distance which the tubular tail may move onto a gun barrel from which the projectile is to be launched, said transverse nozzles being located in said tubular tail in closer proximity to said stop means than to the rear end of said tubular tail, whereby all of said transverse nozzles are adapted to be clear of the barrel of a launching gun before the end of the first half of the displacement of said tubular tail disengaging it from the gun barrel.

4. A projectile as recited in claim 1 wherein said trans verse nozzles are disposed obliquely in the manner of the passages of a centrifugal radial turbine for causing said projectile to spin about its longitudinal axis under the effect of the jets of powder gases escaping through said transverse nozzles.

5. A projectile as recited in claim 1 further including fin elements carried by said tubular tail on the outside thereof opposite the outlets of said transverse nozzles to act as deflectors for the gas jets issuing from said transverse nozzles to cause said projectile to spin about its longitudinal axis.

6. A projectile according to claim 5 in which said fin elements comprise obliquely inclined blades for imparting a torque to the projectile in a given direction about its longitudinal axis during flight.

7. A projectile as recited in claim 1 further including blades carried by said tubular tail on the outside thereof and obliquely inclined with respect to the longitudinal axis thereof to oppose and reduce the initial movement of rotation of the projectile about its longitudinal axis.

8. A projectile adapted to be launched from a gun barrel having a cylindrical surface by the pressure created from a propelling charge in the gun, the gun barrel being of the type which includes a multiplicity of passages extending through its wall in the vicinity of the muzzle, which projectile comprises: a body portion, a tubular tail having its front end fixed to said body portion, said tubular tail having a cylindrical surface adapted to slidably and substantially sealingly engage such a cylindrical surface of the gun from which the projectile is to be fired, a rocket motor carried by said body portion, said rocket motor comprising a reaction charge and a rearwardly directed nozzle opening into said tubular tail at the forward end thereof, and means for causing said projectile to spin about its longitudinal axis, first by utilizing the action of pressurized gases from the combustion of a propelling charge in a launching gun and then by utilizing the reaction eflect of pressurized gases from the combustion of said reaction charge, said means comprising at least two transverse nozzles extending through the wall of said tubular tail rearwardly of the most rearward extension of said body portion, whereby gases issuing through said transverse nozzles have free access to the surrounding atmosphere at least when said transverse nozzles are clear of a gun barrel from which the propectile is to be launched, said tubular tail providing a continuously open path between the rear end of the tail and the rocket motor nozzle whereby hot gases created by the combustion of a propelling charge in a gun from which the projectile is to be launched may pass through the tubular tail and the rocket motor nozzle to ignite said reaction charge, at

5 of a gun from which the projectile is to be launched.

References Cited in the file of this patent UNITED STATES PATENTS 10 1,721,704 Madaschi July 23, 1929 2,507,878 Banning May 16, 1950 2,946,261 Crockett July 26, 1960 FOREIGN PATENTS 502,560 France Feb. 24, 1920 

1. A PROJECTILIE ADAPTED TO BE LAUNCHED FORM A GUN BARREL HAVING A CYLINDRICAL SURFACE BY THE PRESSURE CREATED FROM A PROPELLING CHARGE IN THE GUN, THE GUN BARREL BEING OF THE TYPE WHICH INCLUDES AT LEAST ONE PASSAGE THROUGH ITS WALL IN THE VICINITY OF THE MUZZLE, WHICH PROJECTILE COMPRISES; A BODY PORTION, A TUBULAR TAIL HAVING ITS FRONT END FIXED TO SAID BODY PORTION, SAID TUBULAR TAIL HAVING A CYLINDRICAL SURFACE ADAPTED TO SLIDABLY AND SUBSTANTIALLY SEALINGLY ENGAGE SUCH A CYLINDRICAL SURFACE OF THE GUN FROM WHICH THE PROJECTILE IS TO BE FIRED, A ROCKET MOTOR CARRIED BY SAID BODY PORTION, SAID ROCKET MOTOR COMPRISING A REACTION CHARGE AND A REARWARDLY DIRECTED NOZZLE OPENING INTO A SAID TUBULAR TAIL AT THE FORWARD END THEREOF, AND MEANS FOR CAUSING SAID PROJECTILE TO SPIN ABOUT ITS LONGITUDINAL AXIS, FRIST BY UTILIZING THE ACTION OF PRESSURIZED GASES FROM THE COMBUSTION OF A PROPELLING CHARGE IN A LAUNCHING GUN AND THEN BY UTILIZING THE REACTION EFFECT OF PRESSURIZED GASES FROM THE COMBUSTION OF SAID REACTION CHARGE, SAID MEANS COMPRISING AT LEAST TWO TRANSVERSE NOZZLES EXTENDING THROUGH THE WALL OF SAID TUBULAR TAIL REARWARDLY OF THE MOST REARWARD EXTENSION OF SAID BODY PORTION, WHEREBY GASES ISSUING THROUGH SAID TRANSVERSE NOZZLES HAVE FREE ACCESS TO THE SURROUNDING ATMOSPHERE WHEN SAID TRANSVERSE NOZZLES ARE CLEAR OF A GUN BARREL FROM WHICH THE PROJECTILE IS TO BE LAUNCHED, SAID TUBULAR TAIL PROVIDING A CONTINUOUSLY OPEN PATH BETWEEN THE REAR END OF THE TAIL AND THE ROCKET MOTOR NOZZLE WHEREBY HOT GASES CREATED BY THE COMBUSTION OF A PROPELLING CHARGE IN A GUN FROM WHICH THE PROJECTILE IS TO BE LAUNCHED MAY PASS THROUGH THE TUBULAR TAIL AND THE ROCKET MOTOR NOZZLE TO IGNITE SAID REACTION CHARGE, AT LEAST ONE OF SAID TRANSVERSE NOZZLES BEING PHYSICALLY LOCATED SO AS TO BE SELECTIVELY COMMUNICABLE WITH THE PASSING THROUGH THE BARREL WALL IN THE VICINITY OF THE GUN BARREL MUZZLE WHEN THE PROJECTILE IS MOUNTED ON THE BARREL. 